Many measurements are based on the human body and we all know how sizes and shapes can vary in any group of people. Why choose Goliath as a starting point? Well, the Bible records his height as six cubits and a span. So what was a cubit and what was a span?
It is here that we meet the first of our problems in defining measurements. A span is generally accepted as being the distance between the tips of the little finger and thumb of an open hand. This is about 8 inches on average. However, an old definition of 14 digits equalling one large span makes the large span about 12 inches long if one takes a digit as the width of a fingertip.
The same scale gives the small cubit as being equal to 24 digits. In Ancient Greece the Olympian cubit was defined as 24 fingers where 1 finger was 0.76 inches or just over three quarters of an inch. This gives 18.25 inches for one Olympian cubit. But is the finger the same as the digit?
The cubit was supposed to be the distance between the elbow and the finger tips. In Ancient Babylon the cubit was known as the kus and this was just under 21 inches. The kus was divided into 30 shushi. In Ancient Egypt the cubit was just over 20.5 inches and was subdivided into 28 digits. The Egyptian scale measured 4 digits as a palm, 5 digits as a hand and 12 digits as one small span.
So, depending on which country you happen to be considering, the cubit differs from 18.25 inches to 21 inches. This makes a difference of some 3 inches to the height of Goliath, who was neither a Babylonian nor an Egyptian – and was by all accounts around 11 feet tall, so maybe three inches would not make much difference.
Considering the Romans for a moment, the Romans used feet and 5 feet equalled 1 pace. 1000 paces equalled one mile. This gives the mile as 5000 feet, the modern mile in imperial measurements is 5280 feet. How long is a foot? Well most of us have two, so maybe we should know. A stride is two paces, so as the Romans went marching along, left, right, left, right for every 1000 paces they put a mille stone (mille being Latin for 1000) and this became the mile.
Coming back to the foot – going back a few centuries we find that the legal definition of the foot was that it was the length of the king’s foot. Big king – big foot, small king, small foot. The king could not be everywhere, so people used any convenient foot! The gyrd was then defined using the circumference of the king’s body – or girth. In 1101 Henry 1 decreed that the distance from the tip of his nose to his finger tip was the official definition of the yard. Once again, any nose/finger relationship was used. The yard was divided into three feet and the foot was divided into 12 inches. The legal definition of the inch was “the length of three barleycorns, round and dry, taken from the centre of the ear laid end to end”. So a good year for barley – long inch etc.
So how does this link to financial services? Well many financial instruments are based on measurements, or estimates. We use money to buy many goods by weight, and today’s population, unlike Goliath ( three and one third metres tall) would be unlikely to be happy with the vagaries of weights depending on whether it was a good year for grain or not. Our currency of pounds sterling is based on 100 pence in the pound, but before decimalisation in 1971 there were 240 old pennies to a pound, 12 pence in a shilling and 20 shillings in a pound. “Quid”, a slang word for a pound from pre-decimal times, has survived today.